Bending machines for metal products such as, for example, bars, reinforcement round pieces, structural shapes, tubes or other profiles, with any section shape whatsoever are known, for shaping stirrups or other shaped reinforcement products. Examples of such bending machines are shown in documents WO 2007/141273 A1, WO 03/24640 A1 and WO 2012/143776 A1, all in the name of the present Applicant.
These machines normally consist of a main drawing unit, for example with rollers, which feeds the bars toward a bending unit, and a shearing unit, for example shears, interposed between the main drawing unit and the bending unit, which shears the shaped bars to take them to the size corresponding to the linear development of the segments to be formed.
Since this linear development, or the length of the starter bar when bars are being worked, does not correspond exactly to the length or an exact sub-multiple of the bars sheared, a terminal segment of the bars, or offcut, remains between the drawing unit and the shears, and requires to be removed before a new work cycle is started.
The offcuts, when they do not fall on their own, must therefore be discharged from the axis of advance of the bars; this happens either manually or by suitable expulsion devices.
The manual solution often entails stopping the machine, lifting the cover and removing the segment, with obvious loss of time and problems in terms of safety for the operator.
There are also automated devices which intervene after the shearing has been carried out so that the offcut is discharged, thus freeing the work axis of the shears and drawing unit. However, there is a risk that the discharged offcut may interfere with the bending unit or with other operating units that can be present on the bending machine, compromising the correct functioning thereof and obliging the operator to intervene in any case.
Furthermore, this solution does not guarantee sufficient safety for the operator, since the offcuts are discharged in an uncontrolled manner and can hit the operator.
Another disadvantage is the quantity and length of the offcuts. In other words, the discard of material to be removed from the work cycle is a considerable cost.
These disadvantages can lead to losses in productivity, even considerable, for example where the segment gets jammed, or can lead to injuries to the operator, for example where the thickness is put in an anomalous and unsafe position.
One purpose of the present invention is to obtain a bending machine for metal products, and a corresponding bending method, which allows to discharge the offcuts quickly, easily and safely.
Another purpose of the present invention is to obtain a bending machine that is able to limit the quantity and length of the offcuts to be discharged.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.